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The current implementation of LimitedStream is slow because .read() performs an extra copy into a buffer and .readline() performs two extra copies. The stream being wrapped is already typically a BytesIO object so this is unnecessary. This implementation has largely been untouched for 12 years and, inspired by a simpler implementation in werkzeug, it was possible to achieve the following performance improvement: LimitedStream.read() (single line): Mean +- std dev: [bench_limitedstream-main] 286 ns +- 6 ns -> [bench_limitedstream-patch] 227 ns +- 6 ns: 1.26x faster LimitedStream.readline() (single line): Mean +- std dev: [bench_limitedstream-main] 507 ns +- 11 ns -> [bench_limitedstream-patch] 232 ns +- 8 ns: 2.18x faster LimitedStream.read(8192) (single line): Mean +- std dev: [bench_limitedstream-main] 360 ns +- 8 ns -> [bench_limitedstream-patch] 297 ns +- 6 ns: 1.21x faster LimitedStream.readline(8192) (single line): Mean +- std dev: [bench_limitedstream-main] 602 ns +- 10 ns -> [bench_limitedstream-patch] 305 ns +- 10 ns: 1.98x faster LimitedStream.read() (multiple lines): Mean +- std dev: [bench_limitedstream-main] 290 ns +- 5 ns -> [bench_limitedstream-patch] 236 ns +- 6 ns: 1.23x faster LimitedStream.readline() (multiple lines): Mean +- std dev: [bench_limitedstream-main] 517 ns +- 19 ns -> [bench_limitedstream-patch] 239 ns +- 7 ns: 2.16x faster LimitedStream.read(8192) (multiple lines): Mean +- std dev: [bench_limitedstream-main] 363 ns +- 8 ns -> [bench_limitedstream-patch] 311 ns +- 11 ns: 1.17x faster LimitedStream.readline(8192) (multiple lines): Mean +- std dev: [bench_limitedstream-main] 601 ns +- 12 ns -> [bench_limitedstream-patch] 308 ns +- 7 ns: 1.95x faster Geometric mean: 1.59x faster
The documentation in this tree is in plain text files and can be viewed using any text file viewer. It uses `ReST`_ (reStructuredText), and the `Sphinx`_ documentation system. This allows it to be built into other forms for easier viewing and browsing. To create an HTML version of the docs: * Install Sphinx (using ``python -m pip install Sphinx`` or some other method). * In this docs/ directory, type ``make html`` (or ``make.bat html`` on Windows) at a shell prompt. The documentation in ``_build/html/index.html`` can then be viewed in a web browser. .. _ReST: https://docutils.sourceforge.io/rst.html .. _Sphinx: https://www.sphinx-doc.org/